Khan bathroom is the most ancient bathroom and is situated near the old market (Bazar). ccording to the inscription seen in the main entrance of khan bathroom, it was made by the sheriff of Kurdistan in 1220 during Qajar period. One of the features of Khan bathroom is the height of space and the length of plan. The implementation of decorative design and the usage of stucco decoration and tile lining on the walls throughout the bathroom is one of the most beautiful features of this bathroom. The decorations inside include: Geometry, arabesque, Plants, flowers and flower vase, humanity, animals and birds (Partridge, Pigeon and Peacock) which are used in mixed harmony. The stucco decoration had been used during three different periods and with the passage of time gradually it was changed to natural method. The plan and architecture of bathroom was made in such a way that affected the structure of architecture and the decorations of some of bathroom of Kurdistan and specially the city of Sanandaj. So this building is the pattern in designing and planning the structure in this area. This bathroom and other buildings such as: mosque, squares, market (Bazar) and Chaharbagh for the city development of Sanandaj during Qajar periods. Khan bathroom had special location and role in building the structure of Sanandaj city specially while making the social structure, as the sheriff instead of constructing bathroom around the Bazar he could build around the ancient spaces that were found among the castle. Therefore the questions arises that why the bathroom structure was made there? The second question was that this building what affect it had on architectural structure and stucco decorations? The third question was there any goals for the sheriff and artists, that some of the designs were emphasized on the buildings. By surveying economic and commerce this question were answered and also the development of city in this region had attracted the attention of the governor. The second hypothesis the bathrooms with the description of Khan bathroom in Sanandaj was built in other regions and they were like Khan bathroom. Sheriff of the town by building this bathroom wanted to attract the citizens in order to make developments in this city and other reasons same of the decorations of the bathroom were particularly chosen and special emphasis were done specially the peacock. Although, plans and designs were completely functioned on the complete base of architecture but in general, the designs were dependent on the climates, cultured, social and political reasons through out Iran. Although Khan bathroom was built by native governor but everyone had used this bathroom. Therefore for many reasons it is important, the first the reconstruction, progress, constant ability, renovation, these had been taken into consideration. Second the presentation of the decorations on those time compared to other renovation was exceptional. The third, the development of design in Khan bathroom compared to other masterpiece was effective. This survey is important to building complex, sheriff, naming, historical research description, comparison of space architecture.